Entamobea histolytica Naegleria species Acanthamoeba species

1. Parasitology in district laboratories
 PROTOZOA Single-celled organisms Multiply in human hosts
 Amoebae
Entamoeba histolytica
Acanthamoeba species
Naegleria species
 Flagellates
Giardia lamblia
Trichomonas vaginalis
Trypanosoma species
Leishmania species

2. PRACTICAL CLASSIFICATION
OF PARASITES
 Ciliates Balantidium coli
 Coccidia Blood
and tissue coccidia: Plasmodium species
Toxoplasma
Intestinal coccidia: Isospora
belli Cryptosporidium parvum
Cyclospora cayetanensis

3. PRACTICAL CLASSIFICATION OF PARASITES
 Microsporidia
Encephalitozoon species Enterocytozoon
species
 Paragonimus species Fasciolopsis
buski Fasciola hepatica
Opisthorchis (Clonorchis)
sinensis Opisthorchis viverrini

4. PRACTICAL CLASSIFICATION OF
PARASITES
Cestodes (Tapeworms)
Taenia species Echinococcus
granulosus (larvae) Diphyllobothrium latum
 Nematodes (Roundworms) Intestinal nematodes: Ascaris
lumbricoides (large roundworm) Enterobius
vermicularis (threadworm) Trichuris trichiura
(whipworm)

5. PRACTICAL CLASSIFICATION
OF PARASITES
 Strongyloides stercoralis
Ancylostoma duodenale (hookworm)
Necator americanus(hookworm)
Filarial and other tissue nematodes:
Wuchereria bancrofti
Brugia species
Loa loa
Onchocerca volvulus
Drancunculus medinensis (Guinea worm)
Trichinella species

6. PROTOZOA
 Amoebae: consist of a shapeless mass of moving cytoplasm which
is divided into granular endoplasm and clear ectoplasm.
They move by pushing out the ectoplasm to form pseudopodia (false
feet) into which the endoplasm then flows.
Amoebae reproduce asexually by simply dividing into two (binary
fission) E. histolytica lives in the intestine as a trophozoite, i.e.
vegetative stage of protozoa showing motility and the ability to grow,
feed, and reproduce. It produces resistant cysts by which it is
transmitted.

7. Flagellates
 Flagellates possess at some stage of their life cycle long hair like flagella
They reproduce asexually by binary fission.
G.lamblia is intestinal flagellate that is bilaterally symmetrical having two
nuclei, two axonemes, and four pairs of flagella
Trypanosoma & Leishmania species possess a prominent kinetoplasma
and are transmitted by insects.
Trypanosoma species live in the blood and tissues.
Leishmania species live intracellularly in macrophages.

8. Ciliates
 Ciliates trophozoites are covered with short hairs (cilia) by which
they move. They reproduce
asexually by binary fission and sexually by conjugation.
Ciliates possess two dissimilar nuclei and a large contractile
vacuole. They form cysts by
which they are transmitted.

9. Coccidia
 Coccidia Coccidia are intracellular parasites that reproduce asexually
by a process called schizogony (merogony) and sexually by
sporogony. Plasmodium species
normally found in the liver and red cells, are transmitted by
anopheline mosquitoes. T. gondii and the
intestinal coccidia are transmitted by the ingestion of oocysts.
Intestinal coccidia are particularly important as pathogens in
immunosuppressed or immunodeficient.

10. HELMINTHS
Flukes Flukes are unsegmented mostly flat leaf-like worms
(schistosomes are an exception) without a body cavity. They vary in
size from 1mm (H.heterophyes) to 70mm (F.buski) in length. They
have oral and ventral suckers (attachment organs). The digestive
system consists of a mouth and an oesophagus which divides to form
two intestinal caeca (branched in some species).
There is no anus but an excretory system composed of excretory cells
called flame cells, collecting tubules, and an excretory pore. There is a
simple nervous system.

11. HELMINTHS
 Parasitic fluke
 of medical importance belong to the subclass Digenea.
There is an asexual generation in which multiplication occurs and
a sexual generation which produces eggs.
In humans only the adults are found.
With the exception of schistosomes, flukes are hermaphroditic and
produce eggs that are operculated To develop, the eggs must reach
water.

13. Microsopiridia
 Microsopiridia Microsopridia are obligate intracellular spore-
forming microorganisms, normally pathogenic in fish, insects, and
other invertebrates and mammals. In humans they
have been reported as pathogens in those infected with HIV.
In host cells, there are successive cycles of schizogony followed by
sporogony from which many spores are produced

14. Tapeworms
 Tapeworms The body of a tapeworm is segmented and tapelike and
The scolex has suckers and in some species al
There is no mouth or digestive system. tapeworm
obtains its nutrients through its body surface. There is a simple
excretory system similar to that in flukes. Tapeworms are
hermaphroditic. Proglottids are formed from
behind the head. Newly formed proglottids are small
and immature.

15. Nematodes
 Nematodes Nematodes are cylindrical worms. They
have a body cavity and (skin) which may be smooth, spined,
The adults of some species are very long, e.g. D. medinensis,
measuring 1 metre or more andThe mouth is surrounded by lips, In
some species, e.g. hookworms, the lips open into a buccal cavity
which has cutting and The digestive system is a simple tube which
ends in an anus. There is an
excretory system and a nervous system.

16. Nematodes
 medical importance, important
intestinal nematodes are geohelminths, i.e. soil-transmitted.
A person becomes infected by swallowing infective eggs (A.
lumbricoides, T.trichiura, E.vermicularis) or by infective larvae
penetrating the skin (hookworms, S.stercoralis). Before becoming
adults in their human host the larvae of hookworms, A. lumbricoides,
and S. stercoralis migrate through the heart and lungs for about 10
days during which time the larvae grow and develop.